A few words :
PLANTS :
Twins
Melons
Winters
Cocos
Citrons
Potatoes
Cherries
Just build twins ALWAYS. Potatoes and Cherries for first zombies BUILD Winter Melons at rows 2nd and 4th of column 2. Fill melons at column 1 and 2. Put then cocos at column 4 then citron at column 5.